A factor produced by macrophages in response to endotoxin antagonizes many of the effects of glucocorticoid hormones in laboratory animals and in Reuber hepatoma cells in culture. The factor is to be purified from either serum or a macrophage supernatant fluid. This will permit a number of studies that will distinguish between the action of this factor and others known to be elicited by lipopolysaccharides. The manner in which the factor antagonizes the cortical hormones will be evaluated by quantitating the uptake of radiolabeled dexamethasone by hepatoma cells with and without the factor present. Also to be investigated is the way in which indomethacin induces phosphoenolpyruvate carboxykinase in hepatoma cells. Substances known to block transcription or translation will be used in an attempt to localize the site of action.